From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264499AbUGFWEr (ORCPT ); Tue, 6 Jul 2004 18:04:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264609AbUGFWEr (ORCPT ); Tue, 6 Jul 2004 18:04:47 -0400 Received: from mx1.redhat.com ([66.187.233.31]:17126 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S264499AbUGFWEp (ORCPT ); Tue, 6 Jul 2004 18:04:45 -0400 Date: Tue, 6 Jul 2004 23:04:28 +0100 From: Alasdair G Kergon To: Kevin Corry Cc: Andrew Morton , linux-kernel@vger.kernel.org, dm-devel@redhat.com, torvalds@osdl.org, agk@redhat.com, jim.houston@comcast.net Subject: Re: [PATCH] 1/1: Device-Mapper: Remove 1024 devices limitation Message-ID: <20040706220428.GN30186@agk.surrey.redhat.com> Mail-Followup-To: Kevin Corry , Andrew Morton , linux-kernel@vger.kernel.org, dm-devel@redhat.com, torvalds@osdl.org, agk@redhat.com, jim.houston@comcast.net References: <200407011035.13283.kevcorry@us.ibm.com> <200407021233.09610.kevcorry@us.ibm.com> <20040702124218.0ad27a85.akpm@osdl.org> <200407061323.27066.kevcorry@us.ibm.com> <20040706142335.14efcfa4.akpm@osdl.org> <20040706213552.GA30237@agk.surrey.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040706213552.GA30237@agk.surrey.redhat.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 06, 2004 at 10:35:52PM +0100, Alasdair G Kergon wrote: > Yes, but the comments imply that the thing it found might in some > circumstances not be the thing you asked it to look for To clarify, we make two sorts of requests for ids [minor numbers]: (a) What is the lowest unused id number? (b) Is id number N used or not? If I interpret things correctly, in case (b) if N is larger than the the highest id number currently stored it might still return non-NULL (if lower order bits match lower order bits of a different stored id). [Would it be sufficient for the caller to keep track of the highest allocated ID and check before calling, or is the masking sometimes stronger than that?] Alasdair -- agk@redhat.com